diff --git a/pkgs/development/python-modules/asdf/default.nix b/pkgs/development/python-modules/asdf/default.nix
index b9010b8b444..33513b2289c 100644
--- a/pkgs/development/python-modules/asdf/default.nix
+++ b/pkgs/development/python-modules/asdf/default.nix
@@ -1,54 +1,55 @@
 { lib
+, astropy
 , buildPythonPackage
 , fetchPypi
-, pytest-astropy
-, semantic-version
-, pyyaml
 , jsonschema
-, six
 , numpy
-, isPy27
-, astropy
-, setuptools_scm
-, setuptools
+, packaging
+, pytest-astropy
+, pytestCheckHook
+, pythonOlder
+, pyyaml
+, semantic-version
+, setuptools-scm
 }:
 
 buildPythonPackage rec {
   pname = "asdf";
-  version = "2.7.2";
-  disabled = isPy27;
+  version = "2.7.3";
+  disabled = pythonOlder "3.6";
   format = "pyproject";
 
   src = fetchPypi {
     inherit pname version;
-    sha256 = "4ba2e31cb24b974a11dfae3edee23db2e6bea2d00608604d062366aa3af6e81a";
+    sha256 = "11dyr295wn5m2pcynlwj7kgw9xr66msfvwn1m6a5vv13vzj19spp";
   };
 
+  nativeBuildInputs = [ setuptools-scm ];
+
+  propagatedBuildInputs = [
+    jsonschema
+    numpy
+    packaging
+    pyyaml
+    semantic-version
+  ];
+
   checkInputs = [
     pytest-astropy
     astropy
+    pytestCheckHook
   ];
 
-  propagatedBuildInputs = [
-    semantic-version
-    pyyaml
-    jsonschema
-    six
-    numpy
-    setuptools_scm
-    setuptools
-  ];
-
-  checkPhase = ''
-    PY_IGNORE_IMPORTMISMATCH=1 pytest
+  preCheck = ''
+    export PY_IGNORE_IMPORTMISMATCH=1
   '';
 
+  pythonImportsCheck = [ "asdf" ];
+
   meta = with lib; {
     description = "Python tools to handle ASDF files";
     homepage = "https://github.com/spacetelescope/asdf";
     license = licenses.bsd3;
     maintainers = [ maintainers.costrouc ];
-    # many ValueError in tests
-    broken = true;
   };
 }